Glass vacuum tubes have been widely used in audio applications such as amplification of musical instruments as well as hi-fidelity reproduction. Although solid-state circuit technology has also been developed for use in such audio applications, traditional glass-envelope vacuum tubes are still being used in some audio applications. Modern audio applications often use glass vacuum tubes for their acoustic properties, as well as their esthetic appeal.
Solid-state technology has been acknowledged for cost, performance, manufacturability, and/or other advantages over glass vacuum tubes. Solid-state devices can be significantly less expensive to manufacture, smaller in size, less prone to mechanical failures and wear-out anomalies as compared to glass vacuum tubes. Some solid-state systems and implementations have been developed to emulate the overall functional operation of a glass vacuum tube.
Direct pin-for-pin compatible vacuum tube replacement devices (VTRDs) have also been developed such as is described by the present author in U.S. patent application Ser. No. 11/678,562, titled “VACUUM TUBE REPLACEMENT DEVICE, CIRCUIT AND SYSTEM”. The present disclosure describes solid-state circuits that can be incorporated into VTRDs that enables inaudible signal communication between VTRDs in a target amplification system and further communication to external user interface systems. As will be further described, the present disclosure contemplates applying the described system, circuits and devices in other non-vacuum tube replacement applications.